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DSSTILLTON OF COAL-TAR.

SPECIFICATIONAforming part of Letters Patent No. 252,981, dated January 3l, 1882.

Application filed fipril li, lr'rl. (No model.) Patented in'Engiand Septemberi), 1679. l

To all whom it muy concern:

Be it known that we, (inonde GlinnLnss TREWBY, civil engineer, and HENRY WiLLmM FENNER, mannliicturingchemist, both ot'Beck- 5 ton, in the county ot' Essex, .llnglanih have invented new and usei'ul Improvements in the Distillntion ot Goal-Tar, (for which we have obtained a patent in Great Britain, No. 3,613, bearing date September D, 1579,) which iin- Io proveniente are fully set forth in the following speeiiication, reference being had to the accompanyiug drawings.

' in the distillation of coal-tar as it has been ordinarilycnrried on prior to our invention the x5, heating means to the stills employed hns been that ot the products oi'combastion-applied errternally of such stil'is, and it has been f'ound i necessary to employ such tire-heat nt a much higher temperature, in order to eliminate the 2o heavier oils or products, than their true distilling-points should demand. Thisneeessity i'or undue heat has arisen from tivo causes--tirst, the resistance to the escape ot' the vapors olfered by the viscidity and depth of' the residual products contained in the still; second, the had heat-conductingL properties ot' those residual emitters, preventing the diffusion ofthe heat applied to the still-bottoms, and which equablel diffusion of heat is essential to the attainment ofthe best results. The application to still-bottoms in this Way of excessive fireheat has resulted in the decomposition and loss of vainable products, while the stagnation or Want ol' diffusion ofheat throughout the mass gives rise to carbonization of the pitch and an accumulation ot' colted matter on the interior surfaces ot' the stills more immediately exposed to the fireheat, deadeniug same and obstructing` the ac. tion ofthe fire. periodically to suspend the Working ot'the still in order remove the coke that has thus ac cumulated, whilethenegleet of this precaution has been attended with loss and danger. When heavy oils or coal-tar have hed to be worked this decomposition and coliing of matters adjacent to the sides and bottoms ot' the stills has necessitated frequentrenewals oi'still-bottoms, the cost oi' which, together with the resulting loss ofworlring capacity during the standstill, 5o has been found a serious drawback and a great Hence it has been requisite lossot'proiittotar-distillers. lthasbcenfound, moreover, by tar-(listillers, under systems in general use prior to our improvements, impossible -to burn colte and other highly-heating fnels, although such l'nels were otherwise very 55 accessible and economical in cost. This nnsuitableness arose from the coneeni ration ofthe heat at the bottom ot' the stili whichresuled. 0n the contrary, when norliing under ourimn'ovements we tind that an f' such ob'cction to 6o 7 n i the use otsucli l'uels does not arise, and coke, or, in fact, i'uel oi'any hind that is most accessible, may be employed with safety and success.

'We have discovered that by arranging and applyingnumerousjetsol'stenin,inconjunction 65 with a suitable i'orn'i oi`stilihntloin, in such a manner that n film or sheet of steam is, during` Working, constantly maintained, spreading all .i overtheinieriorsurfaceot'thestili-bottoin,(aiid sides in part,) being interposed between such 7o bottoni andthe matters distilling, we prevent injurious contactot' the pitch with the suriace of thel still-betteln, enablingl the operation oi'boiling thetar to be rendered continuous and safe, and using` less external heat and a more economicnl fuel. t would not ei't'ect the purpose We have in vien' and produce the beneficial re suits we have attained merely to pass steam through pipes or pipes and jets into the mass ofthe tar under distillation in the still, although So some benefit might follow possibly from' the incomplete stirring resulting, il' boiling over were avoided, but sooner or later stagnation et' a portion of the contents i'esiilts,followed by loss ofdii'usionofheat,resultantcarbonization,and 85 coking ot' some of the pitch on the still-bottoms, and the mischief is done, eventually necessitating stoppages of working and loss.

We attain the objects set forth by the ein.

ployinent ofmechanism illustrated in the ac 9e' companying drawings, in n'hich- Figure 1 shows a vertical section, and Fig. 2 a horizontal section, ot' a still and its` steamsupplying parts.

Similar letters refer to similar parts in both 5 views. v i 'hesteain supplied may he oi'n ny con venir-nl; pressure.

Until tlielighter products have been Worked oil by hre-heat, in the usual way, it is not necroo n osmosi essary to employ the steam. These products having passed over, and it becoming requisite to operate on the heavy oils, steam is turned in by the steam-cock A, traversing through the main pipe B, which pipe isconnected with the smaller branch pipes C C C, of which pipes the two outside lead the steam into the ring D, the center one leadsit into the lesser bra-uch pipes E, and these again lead the steam into nun|erous smaller outlet-pipes or distributing-passages F. There are provided as many of these outlet-passages as may be found'neoessary to the proper maintenance 'and disposition ofthe tilm or interposing sheet of steam. The steam thus conveyed, subdivided, and spread out by jets ultimately strikes the gutter and crown of the stiltbcttom, diffusing itself iu a constantly renewing film or sheet, which acts upon Vthe nearest surface or stratum of the mass of tar matters being acted upon,causing it to be constantly renewed. This steam,which, as stated, en'ters through th`e steam-cock A. is, in fact, split up and so divided and subdivided that in its passage through the tubes it becomes, by contact with the vapors and the boiling tar or pitch, super-heated to about the temperature of that tar or pitch, which renders all risk of the tar boiling over, being caused byvany sudden expansion of the steam` impossible, while the increased pressure resulting from that snperheating and expansion while the steam is stillin transit gives increased forcetocause intense agitation ofthe coal-tar4 within theatill, with its resulting diffusion of heat;.and, further, it greatly accelerates the liberation from the tar and expulsion from the still of the con` tained vapors.

Another great advantage and economy that results from our improvements is that from the time when the admission ot'steam through the ppeB and its distributaries has once fairlyfset up proper circulation iu the mass of contained matter it is no longer requisite to increase the tlre which-su`pplies the heat under the still, but it is merely desirable to maintain it j st sutilcently to keep the contents' of the st' l, aided bythe steam, at an even temperature suieien t furthe working, which may from time to time` be ascertained by readings from athermometc r placed within atube which passes from the top to within the still, the end ot' this tube within the still being closed, whereby the contents oi' the still are prevented escaping. f We are aware that rior to our invention it has been proposed to introduce various gases and also steam into .tar-stills to stirthe contents during distillation, but we do not claim the use of steam broadly for such purpose; but

What we do claim isl.- The within-described apparatus for distilling coal-tar, consisting of the main steampipe B, with its controlling-cock A, small brunch pipes C, ring D, lesser branches E, and outlets or jets F, in conjunction with a suitable form of still-bottom, substantially as shown and described.

2. The still t'ordistilling coal-tar, constructed with the 4outer surface of its bottom concave, and provided with a steam-pipe having the ring D and central pipe with branches E, this ring and the branches having numerous'snmll outlctpipes inclined respectivelyto the gutter and to the convex inner surface of the bottom of the still,forminutelysnbdividing the steam and causing it tostrike the crown of the stillbottom and its gutter, as and for the purposes set forth.

In testimony whereof we, GEORGE CARE 'Lass TREWBY and HENRY WILLIAM Furman,

have signed our names to this specillcation in` the presence of two subscribing witnesses.

GEORGE CARELESS TBEWBY. HENRY WILLIAM FENNER. A Witnesses: v

F. J. NAYLQR, J. E. CovEN'foN. 

